/*
 * Copyright (c) 2018-2020 "Graph Foundation,"
 * Graph Foundation, Inc. [https://graphfoundation.org]
 *
 * This file is part of ONgDB Enterprise Edition. The included source
 * code can be redistributed and/or modified under the terms of the
 * GNU AFFERO GENERAL PUBLIC LICENSE Version 3
 * (http://www.fsf.org/licensing/licenses/agpl-3.0.html) as found
 * in the associated LICENSE.txt file.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 */
/*
 * Copyright (c) 2002-2018 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.cluster.statemachine;

import org.neo4j.cluster.com.message.Message;
import org.neo4j.cluster.com.message.MessageType;

/**
 * A single state transition that occurred in
 * a state machine as a consequence of handling a message.
 */
public class StateTransition
{
    private State<?,?> oldState;
    private Message<? extends MessageType> message;
    private State<?,?> newState;

    public StateTransition( State<?,?> oldState, Message<? extends MessageType> message, State<?,?> newState )
    {
        this.oldState = oldState;
        this.message = message;
        this.newState = newState;
    }

    public State<?,?> getOldState()
    {
        return oldState;
    }

    public Message<? extends MessageType> getMessage()
    {
        return message;
    }

    public State<?,?> getNewState()
    {
        return newState;
    }

    @Override
    public boolean equals( Object o )
    {
        if ( this == o )
        {
            return true;
        }
        if ( o == null || getClass() != o.getClass() )
        {
            return false;
        }

        StateTransition that = (StateTransition) o;

        if ( !message.equals( that.message ) )
        {
            return false;
        }
        if ( !newState.equals( that.newState ) )
        {
            return false;
        }
        return oldState.equals( that.oldState );
    }

    @Override
    public int hashCode()
    {
        int result = oldState.hashCode();
        result = 31 * result + message.hashCode();
        result = 31 * result + newState.hashCode();
        return result;
    }

    @Override
    public String toString()
    {
        if ( message.getPayload() instanceof String )
        {
            return getOldState().toString() + "-[" + getMessage().getMessageType() + ":" + getMessage().getPayload() +
                    "]->" + getNewState().toString();
        }
        else
        {
            return getOldState().toString() + "-[" + getMessage().getMessageType() + "]->" + getNewState().toString();
        }
    }
}
